This invention relates to a dental ceramic material and a dental prosthesis. In particular the invention provides a dental ceramic bonder and method of use thereof to form dental prostheses made of titanium or titanium alloys including crowns and bridges. In accordance with the invention dental prostheses are provided which have a strong and permanent bond formed between a bonding dental ceramic coating and a titanium or titanium alloy base.
Mabie et al., U.S. Pat. No. 4,431,451, disclose dental material. Binnes et al., U.S. Pat. No. 4,198,244, disclose fluorescing agents for dental porcelain. Fujui in U.K. Patent GB 2080281 B, discloses biologically active glass and/or glass ceramic compositions and implants coated therewith. Muterthies in European Patent Application 0332887 A2 discloses a process for the manufacture of metal-ceramic dental restorations and color systems. Wuesthoff et al in German Patent Application 2815438 disclose dental porcelain compositions. Yves in Canadian Patent 1177604 discloses metallic prosthesis coated with a vitreous enamel and a method for producing prosthesis dental enamels for nickel and chromium. Mabie et al, Binns et al, Fujui, Muterthies, Wuesthoff et al and Yves do not disclose dental porcelain compositions which have the benefits of the present invention. The compositions therein disclose have coefficients of thermal expansion greater than that of natural tooth material, firing temperatures (melting points) in the range of 900.degree. to 950.degree. C. (which is substantially higher than the maximum firing temperatures for dental ceramic materials coated on titanium), and/or fluoride (which causes corrosion of titanium). These compositions are not adapted to bond to titanium or titanium alloy with a bond strength of at least 20 MPa.
Martin et al in U. S. Pat. No. 4,557,691 disclose a dental porcelain paste and method of using the same. Bowen in U. S. Pat. No. 4,215,033 discloses a composite dental material.
The prior art does not disclose dental ceramic material adapted to bond to titanium or titanium alloy with a bond strength of at least 20 MPa.
It is an object of the present invention to provide a dental ceramic bonding material useful to form dental prostheses having a dental ceramic coating with a bond strength of at least 20 MPa when bonded to a titanium or titanium alloy base.
Throughout this disclosure, the term dental ceramic is defined as meaning any ceramic having a glassy and/or crystalline phase. Pigments as used throughout this disclosure refers to metal oxides which substantially reflect a narrow band of visible light, absorb at least a substantial portion of the remainder of the visible light spectrum and are less than 5% transparent to the broad spectrum of visible light. Opacifiers as used throughout this disclosure refers to metal oxides which reflect at least a substantial portion of a broad spectrum of visible light, and are less than 5% transparent to the broad spectrum of visible light. Clear ceramic material as used throughout this disclosure refers to metal oxides which are fused to a glassy state and which are more than 90% transparent to a broad spectrum of visible light. Network formers as used throughout this disclosure refers to metal oxides such as SiO.sub.2 and Al.sub.1 O.sub.3 which primarily function to strengthen a dental ceramic by network forming. However, as used herein network former does not refer to B.sub.2 O.sub.3. Fluxing metal oxides, also called network modifiers, as used throughout this disclosure refers to metal oxides, such as Li.sub.2 O, Na.sub.2 O, K.sub.2 O, CaO, MgO and BaO, which interrupt strengthening metal oxide networks and effectively reduce the melting temperature of the dental ceramic.